U.S. patent application number 13/211810 was filed with the patent office on 2012-07-05 for low band-gap organic semiconductor compounds, and transistors and electronic devices including the same.
This patent application is currently assigned to SAMSUNG ELECTRONICS CO., LTD.. Invention is credited to Jong Won Chung, Bang Lin Lee, Jeong il Park.
Application Number | 20120168727 13/211810 |
Document ID | / |
Family ID | 45401015 |
Filed Date | 2012-07-05 |
United States Patent
Application |
20120168727 |
Kind Code |
A1 |
Lee; Bang Lin ; et
al. |
July 5, 2012 |
LOW BAND-GAP ORGANIC SEMICONDUCTOR COMPOUNDS, AND TRANSISTORS AND
ELECTRONIC DEVICES INCLUDING THE SAME
Abstract
An organic semiconductor compound including a structural unit
represented by Chemical Formula 1. ##STR00001##
Inventors: |
Lee; Bang Lin; (Suwon-si,
KR) ; Park; Jeong il; (Seongnam-si, KR) ;
Chung; Jong Won; (Hwaseong-si, KR) |
Assignee: |
SAMSUNG ELECTRONICS CO.,
LTD.
Suwon-si
KR
|
Family ID: |
45401015 |
Appl. No.: |
13/211810 |
Filed: |
August 17, 2011 |
Current U.S.
Class: |
257/40 ;
257/E51.025; 526/256; 526/257 |
Current CPC
Class: |
H01L 51/4253 20130101;
C08G 2261/3243 20130101; C08G 61/123 20130101; C08G 2261/3223
20130101; C08G 61/122 20130101; H01L 51/0047 20130101; C08G 2261/92
20130101; H01L 51/0558 20130101; C09B 69/109 20130101; C08G
2261/124 20130101; C08G 2261/414 20130101; C08G 2261/91 20130101;
H01L 51/0036 20130101; H01L 51/0043 20130101; B82Y 10/00 20130101;
C08G 2261/3241 20130101; Y02E 10/549 20130101 |
Class at
Publication: |
257/40 ; 526/256;
526/257; 257/E51.025 |
International
Class: |
H01L 51/30 20060101
H01L051/30; C08F 228/06 20060101 C08F228/06 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 4, 2011 |
KR |
10-2011-0000692 |
Claims
1. An organic semiconductor compound, comprising: at least one
structural unit according to Chemical Formula 1, ##STR00036##
where, in Chemical Formula 1, R.sup.1 and R.sup.2 are each
independently one of selected from hydrogen, a halogen, one of a
substituted and unsubstituted C1-C20 linear or branched alkyl
group, one of a substituted and unsubstituted C3-C20 cycloalkyl
group, one of a substituted and unsubstituted linear or branched
C1-C20 alkoxy group, one of a substituted and unsubstituted C3-C20
cycloalkyloxy group, one of a substituted and unsubstituted C6-C30
aryl group, one of a substituted and unsubstituted C6-C30 aryloxy
group, one of a substituted and unsubstituted C2-C30 heteroaryl
group, and a combination thereof, and selected from a C1-C20 alkyl
group, a C1-C20 alkoxy group, and a C3-C20 cycloalkyl group, where
one of one CH.sub.2 group and a plurality of non-adjacent CH.sub.2
groups are, if R.sup.1 is not hydrogen, optionally substituted with
--O--, --S--, --S(O).sub.2--, --CO--, --OCO--, --C(O)O--,
--CR.sup.51.dbd.CR.sup.52--, --C.ident.C--, and
--SiR.sup.53R.sup.54--, where R.sup.51-R.sup.54 are each
independently selected from hydrogen, one of a substituted and
unsubstituted C1-C15 linear or branched alkyl group, one of a
substituted and unsubstituted C3-C15 cycloalkyl group, one of a
substituted and unsubstituted C1-C15 alkoxy group, one of a
substituted and unsubstituted C6-C15 aryl group, one of a
substituted and unsubstituted C2-C15 heteroaryl group, and a
combination thereof, each X is independently selected from
--CR.sup.3.dbd.N--, --N.dbd.N--, --CR.sup.4.dbd.CR.sup.5--, --O--,
--S--, --Se--, and --NR.sup.6--, Y is selected from
--CR.sup.7.dbd.CR.sup.8--, --O--, --S--, --Se--, and --NR.sup.9--,
R.sup.3-R.sup.9 are each independently one of selected from
hydrogen, a halogen, one of a substituted and unsubstituted C1-C20
linear or branched alkyl group, one of a substituted and
unsubstituted C3-C20 cycloalkyl group, one of a substituted and
unsubstituted linear or branched C1-C20 alkoxy group, one of a
substituted and unsubstituted C3-C20 cycloalkyloxy group, one of a
substituted and unsubstituted C6-C30 aryl group, one of a
substituted and unsubstituted C6-C30 aryloxy group, one of a
substituted and unsubstituted C2-C30 heteroaryl group, and a
combination thereof, selected from a C1-C20 alkyl group, a C1-C20
alkoxy group, and a C3-C20 cycloalkyl group, where one of one
CH.sub.2 group and a plurality of non-adjacent CH.sub.2 groups are
optionally substituted with --O--, --S--, --S(O).sub.2--, --CO--,
--OCO--, --C(O)O--, --CR.sup.51.dbd.CR.sup.52--, --C.ident.C-- and
--SiR.sup.53R.sup.54--, where R.sup.51-R.sup.54 are each
independently selected from hydrogen, one of a substituted and
unsubstituted C1-C15 linear or branched alkyl group, one of a
substituted and unsubstituted C3-C15 cycloalkyl group, one of a
substituted and unsubstituted C1-C15 alkoxy group, one of a
substituted and unsubstituted C6-C15 aryl group, one of a
substituted and unsubstituted C2-C15 heteroaryl group, and a
combination thereof, and when Y is --CR.sup.7.dbd.CR.sup.8--,
adjacent R.sup.7 and R.sup.8 are linked to each other in a fused
ring, Z is selected from one of a substituted and unsubstituted
C1-C40 arylene group, one of a substituted and unsubstituted C4-C14
heteroaromatic ring group, and one of a substituted and
unsubstituted C6-C30 condensed polycyclic group including a
heteroaromatic ring group, and p and q denote a mole ratio of each
structural unit, and p/(p+q) is about 0.5 to about 0.95.
2. The organic semiconductor compound of claim 1, wherein the
organic semiconductor compound comprises a structural unit
according to Chemical Formula 2, ##STR00037## and, in Chemical
Formula 2, R.sup.1, X, Y, Z, p, and q are the same as in Chemical
Formula 1.
3. The organic semiconductor compound of claim 1, wherein p/(p+q)
is about 0.6 to about 0.9.
4. The organic semiconductor compound of claim 2, wherein in
Chemical Formulae 1 and 2, a structural unit according to Chemical
Formula 1A is selected from the structural units according to
Chemical Formula 3, ##STR00038## ##STR00039## and, hydrogen in each
ring of Chemical Formula 3 is optionally substituted with a
substituent selected from one of a substituted and unsubstituted
C1-C15 linear or branched alkyl group, one of a substituted and
unsubstituted C3-C15 cycloalkyl group, one of a substituted and
unsubstituted C1-C15 alkoxy group, one of a substituted and
unsubstituted C6-C15 aryl group, one of a substituted and
unsubstituted C2-C15 heteroaryl group, and a combination
thereof.
5. The organic semiconductor compound of claim 4, wherein in
Chemical Formulae 1 and 2, a --Z-- structural unit is at least one
of the structural units according to Chemical Formula 4,
##STR00040## ##STR00041## in Chemical Formula 4, Q.sup.1 and
Q.sup.2 are each one of S, CR.sup.64R.sup.65, NR.sup.66, and
SiR.sup.67R.sup.68, R.sup.60-R.sup.68 are each independently
selected from hydrogen, one of a substituted and unsubstituted
C1-C15 linear or branched alkyl group, one of a substituted and
unsubstituted C3-C15 cycloalkyl group, one of a substituted and
unsubstituted C1-C15 alkoxy group, one of a substituted and
unsubstituted C6-C15 aryl group, one of a substituted and
unsubstituted C2-C15 heteroaryl group, and a combination thereof,
and hydrogen in each ring of Chemical Formula 4 is optionally
substituted with a substituent selected from one of a substituted
and unsubstituted C1-C15 linear or branched alkyl group, one of a
substituted and unsubstituted C3-C15 cycloalkyl group, one of a
substituted and unsubstituted C1-C15 alkoxy group, one of a
substituted and unsubstituted C6-C15 aryl group, one of a
substituted and unsubstituted C2-C15 heteroaryl group, and a
combination thereof.
6. The organic semiconductor compound of claim 5, comprising a
structural unit according to Chemical Formula 5, ##STR00042## in
Chemical Formula 5, R.sup.1, R.sup.2, X, Y, Z, p, and q are the
same as in Chemical Formula 1, Z' is at least one functional group
according to Chemical Formula 4, Z' being different from Z, and
r/(p+q+r) is less than about 0.2.
7. The organic semiconductor compound of claim 5, wherein the
structural unit of Chemical Formula 1A is at least one of Chemical
Formulae 3-1, 3-4, and 3-7, and the --Z-- structural unit is one of
Chemical Formulae 4-1, 4-3, 4-5, 4-6, 4-8, 4-10, 4-11, or 4-12:
8. The organic semiconductor compound of claim 1, wherein the
organic semiconductor compound including the structural unit
according to Chemical Formula 1 comprises at least one of
structural units according to Chemical Formula 6, ##STR00043##
##STR00044## in Chemical Formula 6, Ra--Rg are each independently
selected from hydrogen, one of a substituted and unsubstituted
C1-C20 linear or branched alkyl group, and one of a substituted and
unsubstituted C1-C20 linear or branched alkoxy group, p/(p+q) is
about 0.5 to about 0.95, and r/(p+q+r) is less than about 0.2.
9. The organic semiconductor compound of claim 1, wherein a number
average molecular weight (Mn) of the organic semiconductor compound
is about 5,000 to about 200,000.
10. The organic semiconductor compound of claim 1, wherein a weight
average molecular weight (Mw) of the organic semiconductor compound
is about 10,000 to about 500,000.
11. The organic semiconductor compound of claim 1, wherein the
organic semiconductor compound is p-type.
12. A transistor comprising the organic semiconductor compound of
claim 1.
13. The transistor of claim 12, wherein the transistor includes:
source and drain electrodes on a substrate; a gate electrode
between the source and drain electrodes; an insulation layer
separating the source electrode, the drain electrode, and the gate
electrode; and an active layer including the organic semiconductor
compound in a channel region between the source and drain
electrodes.
14. An electronic device comprising the organic semiconductor
compound of claim 1.
15. The electronic device of claim 14, wherein the electronic
device is a solar cell.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority under 37 U.S.C. .sctn.119
to Korean Patent Application No. 10-2011-0000692, filed on Jan. 4,
2011 in the Korean Intellectual Property Office (KIPO), the entire
contents of which is incorporated herein by reference.
BACKGROUND
[0002] 1. Field
[0003] Example embodiments relate to low band gap organic
semiconductor compounds, transistors including the same and/or
electronic devices including the same.
[0004] 2. Description of the Related Art
[0005] As a society becomes information-oriented, development of a
new image display device that overcomes the drawbacks of a
conventional cathode ray tube (CRT) (e.g., heavy weight and large
volume) may be required. Accordingly, various flat panel displays
such as a liquid crystal display (LCD), an organic light emitting
diode (OLED) display, a plasma display panel (PDP), a
surface-conduction electron-emitter display (SED), and so on, are
drawing attention.
[0006] As for a switching device of the flat panel displays, a thin
film transistor (TFT) including amorphous silicon as a
semiconductor layer is widely used. The amorphous silicon thin film
transistor is widely used because it may have good uniformity and
high electrical properties in a doping state, but good insulating
properties in a non-doping state. However, in order to deposit a
conventional amorphous silicon thin film transistor on a substrate,
the deposition process may be performed at a relatively high
temperature of about 300.degree. C. Therefore, this process is
difficult to apply to low-temperature substrates (e.g., polymer
substrates and the like) to accomplish a flexible display.
[0007] An organic thin film transistor (OTFT) using an organic
semiconductor material has been suggested. The organic thin film
transistor generally includes a substrate, a gate electrode, an
insulation layer, a source electrode, a drain electrode, and a
channel region. The organic thin film transistor may be classified
into a bottom contact (BC) type in which a channel region is formed
on the source electrode and the drain electrode and a tap contact
(TC) type in which a metal electrode is formed beneath the channel
region due to mask deposition and the like.
[0008] The low molecular or oligomer organic semiconductor material
filled in the channel region of the organic thin film transistor
(OTFT) may include merocyanine, phthalocyanine, perylene,
pentacene, C60, a thiophene oligomer, and so on. The low molecular
or oligomer organic semiconductor material may be a thin film
formed on the channel region mainly according to a vacuum process.
On the other hand, an organic semiconductor polymer material has a
workability advantage of large-area processing with a low cost in a
solution method such as printing techniques.
SUMMARY
[0009] At least some example embodiments may provide organic
semiconductor compounds with excellent and/or improved charge
mobility fabricated using a solution process. Other example
embodiments may provide transistors including the organic
semiconductor compounds. Further example embodiments may provide
electronic devices including the organic semiconductor
compounds.
[0010] According to some example embodiments, an organic
semiconductor compound includes a structural unit represented by
the following Chemical Formula 1.
##STR00002##
[0011] In Chemical Formula 1, R.sup.1 and R.sup.2 are each
independently selected from hydrogen, a halogen, a substituted or
unsubstituted C1-C20 linear or branched alkyl group, a substituted
or unsubstituted C3-C20 cycloalkyl group, a substituted or
unsubstituted linear or branched C1-C20 alkoxy group, a substituted
or unsubstituted C3-C20 cycloalkyloxy group, a substituted or
unsubstituted C6-C30 aryl group, a substituted or unsubstituted
C6-C30 aryloxy group, a substituted or unsubstituted C2-C30
heteroaryl group, and a combination thereof, or a C1-C20 alkyl
group, a C1-C20 alkoxy group, or a C3-C20 cycloalkyl group where
one CH.sub.2 group or two or more non-adjacent CH.sub.2 groups are
optionally substituted with --O--, --S--, --S(O).sub.2--, --CO--,
--OCO--, --C(O)O--, --CR.sup.51.dbd.CR.sup.52--, --C.ident.C--, and
--SiR.sup.53R.sup.54-- (where R.sup.51-R.sup.54 are each
independently selected from hydrogen, a substituted or
unsubstituted C1-C15 linear or branched alkyl group, a substituted
or unsubstituted C3-C15 cycloalkyl group, a substituted or
unsubstituted C1-C15 alkoxy group, a substituted or unsubstituted
C6-C15 aryl group, a substituted or unsubstituted C2-C15 heteroaryl
group, and a combination thereof), provided that R.sup.1 is not
hydrogen.
[0012] X is each independently selected from --CR.sup.3.dbd.N--,
--N.dbd.N--, --CR.sup.4.dbd.CR.sup.5--, --O--, --S--, --Se--, and
--NR.sup.6--, Y is selected from --CR.sup.7.dbd.CR.sup.8--, --O--,
--S--, --Se--, and --NR.sup.9--, R.sup.3 to R.sup.9 are each
independently selected from hydrogen, a halogen, a substituted or
unsubstituted C1-C20 linear or branched alkyl group, a substituted
or unsubstituted C3-C20 cycloalkyl group, a substituted or
unsubstituted linear or branched C1-C20 alkoxy group, a substituted
or unsubstituted C3-C20 cycloalkyloxy group, a substituted or
unsubstituted C6-C30 aryl group, a substituted or unsubstituted
C6-C30 aryloxy group, a substituted or unsubstituted C2-C30
heteroaryl group, and a combination thereof; a C10-C20 alkyl group,
a C1-C20 alkoxy group, or a C3-C20 cycloalkyl group where one
CH.sub.2 group or two or more non-adjacent CH.sub.2 groups are
optionally substituted with --O--, --S--, --S(O).sub.2--, --CO--,
--OCO--, --C(O)O--, --CR.sup.51.dbd.CR.sup.52--, --C.ident.C-- and
--SiR.sup.53R.sup.54-- (where R.sup.51-R.sup.54 are each
independently selected from hydrogen, a substituted or
unsubstituted C1-C15 linear or branched alkyl group, a substituted
or unsubstituted C3-C15 cycloalkyl group, a substituted or
unsubstituted C1-C15 alkoxy group, a substituted or unsubstituted
C6-C15 aryl group, a substituted or unsubstituted C2-C15 heteroaryl
group, and a combination thereof); or when Y is
--CR.sup.7.dbd.CR.sup.8--, adjacent R.sup.7 and Ware linked to each
other to provide a fused ring, Z is a substituted or unsubstituted
C1-C40 arylene group, a substituted or unsubstituted C4-C14
heteroaromatic ring group, or a substituted or unsubstituted C6-C30
condensed polycyclic group including a heteroaromatic ring group,
and p and q denotes a mole ratio of each structural unit, and
p/(p+q) ranges from about 0.5 to about 0.95.
[0013] The organic semiconductor compound may include a structural
unit represented by the following Chemical Formula 2.
##STR00003##
[0014] In Chemical Formula 2, R.sup.1, X, Y, Z, p, and q are the
same as in Chemical Formula 1. In Chemical Formulae 1 and 2,
p/(p+q) may range from about 0.5 to about 0.95. In Chemical
Formulae 1 and 2, the structural unit represented by the following
Chemical Formula 1A may be selected from the structural units
represented by the following Chemical Formula 3.
##STR00004## ##STR00005##
[0015] Hydrogen in each ring of Chemical Formula 3 may be
substituted with a substituent selected from a substituted or
unsubstituted C1-C15 linear or branched alkyl group, a substituted
or unsubstituted C3-C15 cycloalkyl group, a substituted or
unsubstituted C1-C15 alkoxy group, a substituted or unsubstituted
C6-C15 aryl group, a substituted or unsubstituted C2-C15 heteroaryl
group, and a combination thereof. In Chemical Formulae 1 and 2, a
--Z-- structural unit is at least one of the structural units
represented by the following Chemical Formula 4.
##STR00006## ##STR00007##
[0016] In Chemical Formula 4, Q.sup.1 and Q.sup.2 are each S,
CR.sup.64R.sup.65, NR.sup.66 or SiR.sup.67R.sup.68, where
R.sup.60-R.sup.68 are each independently selected from hydrogen, a
substituted or unsubstituted C1-C15 linear or branched alkyl group,
a substituted or unsubstituted C3-C15 cycloalkyl group, a
substituted or unsubstituted C1-C15 alkoxy group, a substituted or
unsubstituted C6-C15 aryl group, a substituted or unsubstituted
C2-C15 heteroaryl group, and a combination thereof, and hydrogen in
each ring of Chemical Formula 4 may be substituted with a
substituent selected from a substituted or unsubstituted C1-C15
linear or branched alkyl group, a substituted or unsubstituted
C3-C15 cycloalkyl group, a substituted or unsubstituted C1-C15
alkoxy group, a substituted or unsubstituted C6-C15 aryl group, a
substituted or unsubstituted C2-C15 heteroaryl group, and a
combination thereof.
[0017] The organic semiconductor compound including the structural
unit of Chemical Formula 1 or the structural unit of Chemical
Formula 2 may include a structural unit represented by the
following Chemical Formula 5.
##STR00008##
[0018] In Chemical Formula 5, R.sup.1, R.sup.2, X, Y, Z, p, and q
are the same as in Chemical Formula 1, Z' is at least one of
functional groups represented by the above Chemical Formula 4, and
Z' is different from Z, and r/(p+q+r) is in a range of about 0.2 or
less and specifically about 0.05 to about 0.15. The structural unit
of Chemical Formula 1A in Chemical Formula 1 may be at least one of
Chemical Formulae 3-1, 3-4, and 3-7, and the --Z-- structural unit
in Chemical Formula 1 may be one of Chemical Formulae 4-1, 4-3,
4-5, 4-6, 4-8, 4-10, 4-11, or 4-12.
[0019] The organic semiconductor compound including the structural
unit represented by Chemical Formula 1 may include at least one of
structural units represented by the following Chemical Formula
6.
##STR00009## ##STR00010##
[0020] In Chemical Formula 6, Ra--Rg are each independently
selected from hydrogen, a substituted or unsubstituted C1-C20
linear or branched alkyl group, or a substituted or unsubstituted
C1-C20 linear or branched alkoxy group, p/(p+q) ranges from about
0.5 to about 0.95, and r/(p+q+r) is about 0.2 or less. The organic
semiconductor compound may have a number average molecular weight
(Mn) of about 5,000 to about 200,000, and a weight average
molecular weight (Mn) of about 10,000 to about 500,000. The organic
semiconductor compound may be a p-type organic semiconductor
compound.
[0021] According to other example embodiments, a transistor
including the organic semiconductor compound is provided. The
transistor includes a gate electrode positioned on a substrate, a
source electrode and a drain electrode facing each other and
defining a channel region, an insulation layer that electrically
insulates the source electrode and drain electrode from the gate
electrode, and an active layer including the organic semiconductor
compound in the channel region. According to still other example
embodiments, an electronic device including the organic
semiconductor compound is provided. The electronic device may be an
organic solar cell.
[0022] According to at least one example embodiment, an organic
semiconductor compound includes at least one structural unit
according to Chemical Formula 1, where, in Chemical Formula 1,
R.sup.1 and R.sup.2 are each independently one of selected from
hydrogen, a halogen, one of a substituted and unsubstituted C1-C20
linear or branched alkyl group, one of a substituted and
unsubstituted C3-C20 cycloalkyl group, one of a substituted and
unsubstituted linear or branched C1-C20 alkoxy group, one of a
substituted and unsubstituted C3-C20 cycloalkyloxy group, one of a
substituted and unsubstituted C6-C30 aryl group, one of a
substituted and unsubstituted C6-C30 aryloxy group, one of a
substituted and unsubstituted C2-C30 heteroaryl group, and a
combination thereof, and selected from a C1-C20 alkyl group, a
C1-C20 alkoxy group, and a C3-C20 cycloalkyl group.
[0023] One of one CH.sub.2 group and a plurality of non-adjacent
CH.sub.2 groups are, if R.sup.1 is not hydrogen, optionally
substituted with --O--, --S--, --S(O).sub.2--, --CO--, --OCO--,
--C(O)O--, --CR.sup.51.dbd.CR.sup.52--, --C.ident.C--, and
--SiR.sup.53R.sup.54--, where R.sup.51-R.sup.54 are each
independently selected from hydrogen, one of a substituted and
unsubstituted C1-C15 linear or branched alkyl group, one of a
substituted and unsubstituted C3-C15 cycloalkyl group, one of a
substituted and unsubstituted C1-C15 alkoxy group, one of a
substituted and unsubstituted C6-C15 aryl group, one of a
substituted and unsubstituted C2-C15 heteroaryl group, and a
combination thereof, each X is independently selected from
--CR.sup.3.dbd.N--, --N.dbd.N--, --CR.sup.4.dbd.CR.sup.5--, --O--,
--S--, --Se--, and --NR.sup.6--.
[0024] Y is selected from --CR.sup.7.dbd.CR.sup.8--, --O--, --S--,
--Se--, and --NR.sup.9--, R.sup.3-R.sup.9 are each independently
one of selected from hydrogen, a halogen, one of a substituted and
unsubstituted C1-C20 linear or branched alkyl group, one of a
substituted and unsubstituted C3-C20 cycloalkyl group, one of a
substituted and unsubstituted linear or branched C1-C20 alkoxy
group, one of a substituted and unsubstituted C3-C20 cycloalkyloxy
group, one of a substituted and unsubstituted C6-C30 aryl group,
one of a substituted and unsubstituted C6-C30 aryloxy group, one of
a substituted and unsubstituted C2-C30 heteroaryl group, and a
combination thereof, selected from a C1-C20 alkyl group, a C1-C20
alkoxy group, and a C3-C20 cycloalkyl group, where one of one
CH.sub.2 group and a plurality of non-adjacent CH.sub.2 groups are
optionally substituted with --O--, --S--, --S(O).sub.2--, --CO--,
--OCO--, --C(O)O--, --CR.sup.51.dbd.CR.sup.52--, --C.ident.C-- and
--SiR.sup.53R.sup.54--.
[0025] R.sup.51-R.sup.54 are each independently selected from
hydrogen, one of a substituted and unsubstituted C1-C15 linear or
branched alkyl group, one of a substituted and unsubstituted C3-C15
cycloalkyl group, one of a substituted and unsubstituted C1-C15
alkoxy group, one of a substituted and unsubstituted C6-C15 aryl
group, one of a substituted and unsubstituted C2-C15 heteroaryl
group, and a combination thereof, and when Y is
--CR.sup.7.dbd.CR.sup.8--, adjacent R.sup.7 and R.sup.8 are linked
to each other in a fused ring, Z is selected from one of a
substituted and unsubstituted C1-C40 arylene group, one of a
substituted and unsubstituted C4-C14 heteroaromatic ring group, and
one of a substituted and unsubstituted C6-C30 condensed polycyclic
group including a heteroaromatic ring group, and p and q denote a
mole ratio of each structural unit, and p/(p+q) is about 0.5 to
about 0.95.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Example embodiments will be more clearly understood from the
following brief description taken in conjunction with the
accompanying drawings. FIGS. 1-7 represent non-limiting, example
embodiments as described herein.
[0027] FIG. 1 is a schematic cross-sectional diagram illustrating
transistors according to some example embodiments;
[0028] FIG. 2 is a schematic cross-sectional diagram illustrating
transistors according to other example embodiments;
[0029] FIG. 3 is a schematic cross-sectional diagram illustrating
organic solar cells according to still other example
embodiments;
[0030] FIG. 4 is .sup.1H NMR spectrum of an organic semiconductor
polymer represented by Chemical Formula 6-1 (3) according to
Example 1;
[0031] FIG. 5 is .sup.1H NMR spectrum of an organic semiconductor
polymer represented by Chemical Formula 6-1 (2) according to
Example 2;
[0032] FIG. 6 is UV-vis absorption spectrum of a film including the
organic semiconductor polymer represented by Chemical Formula 6-1
(3) according to Example 1; and
[0033] FIG. 7 is a graph illustrating a current density-voltage
(J.sub.sc-V.sub.oc) measurement of an organic solar cell including
a mixture of the organic semiconductor polymer represented by the
Chemical Formula 6-1 (2) according to Example 2 and PCBM in a
weight ratio of 1:1.
[0034] It should be noted that these figures are intended to
illustrate the general characteristics of methods, structure and/or
materials utilized in certain example embodiments and to supplement
the written description provided below. These drawings are not,
however, to scale and may not precisely reflect the precise
structural or performance characteristics of any given embodiment,
and should not be interpreted as defining or limiting the range of
values or properties encompassed by example embodiments. For
example, the relative thicknesses and positioning of molecules,
layers, regions and/or structural elements may be reduced or
exaggerated for clarity. The use of similar or identical reference
numbers in the various drawings is intended to indicate the
presence of a similar or identical element or feature.
DETAILED DESCRIPTION
[0035] Example embodiments will now be described more fully with
reference to the accompanying drawings, in which example
embodiments are shown. Example embodiments may, however, be
embodied in many different forms and should not be construed as
being limited to the embodiments set forth herein; rather, these
embodiments are provided so that this disclosure will be thorough
and complete, and will fully convey the concept of example
embodiments to those of ordinary skill in the art. In the drawings,
the thicknesses of layers and regions are exaggerated for clarity.
Like reference numerals in the drawings denote like elements, and
thus their description will be omitted.
[0036] It will be understood that when an element is referred to as
being "connected" or "coupled" to another element, it can be
directly connected or coupled to the other element or intervening
elements may be present. In contrast, when an element is referred
to as being "directly connected" or "directly coupled" to another
element, there are no intervening elements present. Like numbers
indicate like elements throughout. As used herein the term "and/or"
includes any and all combinations of one or more of the associated
listed items. Other words used to describe the relationship between
elements or layers should be interpreted in a like fashion (e.g.,
"between" versus "directly between," "adjacent" versus "directly
adjacent," "on" versus "directly on").
[0037] It will be understood that, although the terms "first",
"second", etc. may be used herein to describe various elements,
components, regions, layers and/or sections, these elements,
components, regions, layers and/or sections should not be limited
by these terms. These terms are only used to distinguish one
element, component, region, layer or section from another element,
component, region, layer or section. Thus, a first element,
component, region, layer or section discussed below could be termed
a second element, component, region, layer or section without
departing from the teachings of example embodiments.
[0038] Spatially relative terms, such as "beneath," "below,"
"lower," "above," "upper" and the like, may be used herein for ease
of description to describe one element or feature's relationship to
another element(s) or feature(s) as illustrated in the figures. It
will be understood that the spatially relative terms are intended
to encompass different orientations of the device in use or
operation in addition to the orientation depicted in the figures.
For example, if the device in the figures is turned over, elements
described as "below" or "beneath" other elements or features would
then be oriented "above" the other elements or features. Thus, the
exemplary term "below" can encompass both an orientation of above
and below. The device may be otherwise oriented (rotated 90 degrees
or at other orientations) and the spatially relative descriptors
used herein interpreted accordingly.
[0039] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
example embodiments. As used herein, the singular forms "a," "an"
and "the" are intended to include the plural forms as well, unless
the context clearly indicates otherwise. It will be further
understood that the terms "comprises", "comprising", "includes"
and/or "including," if used herein, specify the presence of stated
features, integers, steps, operations, elements and/or components,
but do not preclude the presence or addition of one or more other
features, integers, steps, operations, elements, components and/or
groups thereof.
[0040] Example embodiments are described herein with reference to
cross-sectional illustrations that are schematic illustrations of
idealized embodiments (and intermediate structures) of example
embodiments. As such, variations from the shapes of the
illustrations as a result, for example, of manufacturing techniques
and/or tolerances, are to be expected. Thus, example embodiments
should not be construed as limited to the particular shapes of
regions illustrated herein but are to include deviations in shapes
that result, for example, from manufacturing. For example, an
implanted region illustrated as a rectangle may have rounded or
curved features and/or a gradient of implant concentration at its
edges rather than a binary change from implanted to non-implanted
region. Likewise, a buried region formed by implantation may result
in some implantation in the region between the buried region and
the surface through which the implantation takes place. Thus, the
regions illustrated in the figures are schematic in nature and
their shapes are not intended to illustrate the actual shape of a
region of a device and are not intended to limit the scope of
example embodiments.
[0041] Unless otherwise defined, all terms (including technical and
scientific terms) used herein have the same meaning as commonly
understood by one of ordinary skill in the art to which example
embodiments belong. It will be further understood that terms, such
as those defined in commonly-used dictionaries, should be
interpreted as having a meaning that is consistent with their
meaning in the context of the relevant art and will not be
interpreted in an idealized or overly formal sense unless expressly
so defined herein.
[0042] As used herein, when a definition is not otherwise provided,
the term "heteroaromatic ring group" may refer to a C2-C30
heteroaryl group, a C3-C30 heterocycloalkenyl group, or a C3-C30
heterocycloalkynyl group. The term "condensed polycyclic group" may
refer to a fused ring where at least one ring selected from a
C3-C30 cycloalkyl group, a C3-C30 cycloalkenyl group, a C2-C30
heterocycloalkyl group, a C2-C30 heteroaryl group, and a C3-C30
heterocycloalkenyl group, and the heteroaromatic ring group are
linked to each other. As used herein, when specific definition is
not otherwise provided, the prefix "hetero" refers to one including
heteroatoms selected from the group consisting of N, O, S, Si, and
P, and including 1-4 heteroatoms in one ring.
[0043] As used herein, when specific definition is not otherwise
provided, the term "substituted" refers to one substituted with at
least one functional group selected from the group consisting of a
fluoro group, a C1-C30 linear or branched alkyl group, a C3-C30
cycloalkyl group, a C1-C20 fluoroalkyl group, a C1-C20
perfluoroalkyl group (C.sub.nF.sub.2n+1), a C1-C30 linear or
branched alkoxy group, a C3-C30 cycloalkoxy group, a C2-C30 linear
or branched alkoxyalkyl group, a C4-C30 cycloalkoxyalkyl group, and
a combination thereof, in a functional group or a compound.
[0044] According to at least one example embodiment, an organic
semiconductor compound represented by the following Chemical
Formula 1 is provided.
##STR00011##
[0045] In Chemical Formula 1, R.sup.1 and R.sup.2 may each
independently be selected from hydrogen, a halogen, a substituted
or unsubstituted C1-C20 linear or branched alkyl group, a
substituted or unsubstituted C3-C20 cycloalkyl group, a substituted
or unsubstituted linear or branched C1-C20 alkoxy group, a
substituted or unsubstituted C3-C20 cycloalkyloxy group, a
substituted or unsubstituted C6-C30 aryl group, a substituted or
unsubstituted C6-C30 aryloxy group, a substituted or unsubstituted
C2-C30 heteroaryl group, and a combination thereof, or a C1-C20
alkyl group, a C1-C20 alkoxy group, or a C3-C20 cycloalkyl group,
where one CH.sub.2 group or two or more non-adjacent CH.sub.2
groups may be substituted with --O--, --S--, --S(O).sub.2--,
--CO--, --OCO--, --C(O)O--, --CR.sup.51.dbd.CR.sup.52--,
--C.ident.C--, and --SiR.sup.53R.sup.54--, where R.sup.51-R.sup.54
are each independently selected from hydrogen, a substituted or
unsubstituted C1-C15 linear or branched alkyl group, a substituted
or unsubstituted C3-C15 cycloalkyl group, a substituted or
unsubstituted C1-C15 alkoxy group, a substituted or unsubstituted
C6-C15 aryl group, a substituted or unsubstituted C2-C15 heteroaryl
group, and a combination thereof, provided, as one example, that
R.sup.1 is not hydrogen
[0046] X each may be independently selected from
--CR.sup.3.dbd.N--, --N.dbd.N--, --CR.sup.4.dbd.CR.sup.5--, --O--,
--S--, --Se--, and --NR.sup.6--, Y may be selected from
--CR.sup.7.dbd.CR.sup.8--, --O--, --S--, --Se--, and --NR.sup.9--.
R.sup.3-R.sup.9 each may be independently selected from hydrogen, a
halogen, a substituted or unsubstituted C1-C20 linear or branched
alkyl group, a substituted or unsubstituted C3-C20 cycloalkyl
group, a substituted or unsubstituted linear or branched C1-C20
alkoxy group, a substituted or unsubstituted C3-C20 cycloalkyloxy
group, a substituted or unsubstituted C6-C30 aryl group, a
substituted or unsubstituted C6-C30 aryloxy group, a substituted or
unsubstituted C2-C30 heteroaryl group, and a combination thereof; a
C1-C20 alkyl group, a C1-C20 alkoxy group, or a C3-C20 cycloalkyl
group where one CH.sub.2 group or two or more non-adjacent CH.sub.2
groups may be substituted with --O--, --S--, --S(O).sub.2--,
--CO--, --OCO--, --C(O)O--, --CR.sup.51.dbd.CR.sup.52--,
--C.ident.C-- and --SiR.sup.53R.sup.54-- (where R.sup.51-R.sup.54
each may independently be selected from hydrogen, a substituted or
unsubstituted C1-C15 linear or branched alkyl group, a substituted
or unsubstituted C3-C15 cycloalkyl group, a substituted or
unsubstituted C1-C15 alkoxy group, a substituted or unsubstituted
C6-C15 aryl group, a substituted or unsubstituted C2-C15 heteroaryl
group, and a combination thereof); or when Y is
--CR.sup.7.dbd.CR.sup.8--, adjacent R.sup.7 and R.sup.8 may be
linked to each other to provide a fused ring.
[0047] Z may be a substituted or unsubstituted C1-C40 arylene
group, a substituted or unsubstituted C4-C14 heteroaromatic ring
group, or a substituted or unsubstituted C6-C30 condensed
polycyclic group including a heteroaromatic ring group, and p and q
may denote a mole ratio of each structural unit, and p/(p+q) may be
about 0.5 to about 0.95, for example, about 0.6 to about 0.9 (e.g.,
about 0.7 to about 0.8). When p is within the range, the organic
semiconductor compound may lower an energy band gap down to a
desired range while maintaining coplanarity.
[0048] The organic semiconductor compound may include a structural
unit represented by the following Chemical Formula 2.
##STR00012##
[0049] In Chemical Formula 2, R.sup.1, X, Y, Z, p, and q may be the
same as in Chemical Formula 1. In Chemical Formulae 1 and 2,
p/(p+q) may be about 0.5 to about 0.95. In Chemical Formula 1, a
thiophene structural unit having a R.sup.1 substituent, a
structural unit represented by the following Chemical Formula 1A,
and an --Z-- structural unit may be alternately arranged in the
mole ratio (mole fraction). The thiophene structural unit with
R.sup.1 substituent may have regioregularity (a Head-to-Tail
structure) where the R.sup.1 substituent is regularly arranged at a
specific site.
##STR00013##
[0050] In Chemical Formula 1, the thiophene structural unit
including an R.sup.1 substituent may be included in an amount of
about 0.5 or more based on the amount (p+q) of the total structural
units, and may improve coplanarity of a compound and increase
charge transfer. The organic semiconductor compound with excellent
and/or improved coplanarity may bring about good and/or improved
semiconductor characteristics and may be usefully applied to
transistors. The R.sup.1 substituent may have regioregularity and
may improve interaction with an n-type structure and control
intermolecular interaction. This organic semiconductor compound may
have excellent and/or improved miscibility with CNT, fullerene,
graphene, and the like and may be used in an organic solar cell and
the like.
[0051] In Chemical Formulae 1 and 2, the structural unit
represented by Chemical Formula 1A may be selected from the
structural units represented by the following Chemical Formula 3.
The structural unit represented by the above Chemical Formula 1A
may decrease the band gap of an organic semiconductor compound.
##STR00014## ##STR00015##
[0052] Hydrogen in each ring of Chemical Formula 3 may be
substituted with a substituent selected from a substituted or
unsubstituted C1-C15 linear or branched alkyl group, a substituted
or unsubstituted C3-C15 cycloalkyl group, a substituted or
unsubstituted C1-C15 alkoxy group, a substituted or unsubstituted
C6-C15 aryl group, a substituted or unsubstituted C2-C15 heteroaryl
group, and a combination thereof.
[0053] The --Z-- structural unit may control UV absorption
coefficient. In Chemical Formulae 1 and 2, the --Z-- structural
unit may be at least one of the structural units represented by the
following Chemical Formula 4.
##STR00016## ##STR00017##
[0054] In Chemical Formula 4, Q.sup.1 and Q.sup.2 may each be S,
CR.sup.64R.sup.65, NR.sup.66 or SiR.sup.67R.sup.68, where
R.sup.60-R.sup.68 are each independently selected from hydrogen, a
substituted or unsubstituted C1-C15 linear or branched alkyl group,
a substituted or unsubstituted C3-C15 cycloalkyl group, a
substituted or unsubstituted C1-C15 alkoxy group, a substituted or
unsubstituted C6-C15 aryl group, a substituted or unsubstituted
C2-C15 heteroaryl group, and a combination thereof. Hydrogen in
each ring of Chemical Formula 4 may be substituted with a
substituent selected from a substituted or unsubstituted C1-C15
linear or branched alkyl group, a substituted or unsubstituted
C3-C15 cycloalkyl group, a substituted or unsubstituted C1-C15
alkoxy group, a substituted or unsubstituted C6-C15 aryl group, a
substituted or unsubstituted C2-C15 heteroaryl group, and a
combination thereof.
[0055] The organic semiconductor compound including structural
units represented by the above Chemical Formulae 1 and 2 may
include one of functional groups represented by Chemical Formulas
4-1 to 4-13 (Chemical Formula 4) and a combination thereof as a
(e.g., an additional structural unit). The functional groups may
have a different structure from the --Z-- structural unit included
in Chemical Formula 1 or 2. For example, a structural unit (Z')
additionally included in Chemical Formula 1 may be represented in
the following Chemical Formula 5.
##STR00018##
[0056] R.sup.1, R.sup.2, X, Y, Z, p, and q may be the same as in
Chemical Formula 1, Z' may be at least one of functional groups
represented by the above Chemical Formula 4, Z' may be different
from Z, and r/(p+q+r) may be about 0.05 to about 0.2 or less, for
example, about 0.05 to about 0.15. A --Z'-- structural unit
including the functional group may be included in an amount of
about 20.0 moles or less based on 100 moles of the structural unit
of Chemical Formula 1, and according to other example embodiments,
in an amount of about 5 moles to about 15 moles. When the --Z'--
structural unit including a functional group of Chemical Formula 4
is included within the range, the --Z'-- structural unit may not
deteriorate properties of an organic semiconductor compound and may
also introduce various structural units.
[0057] The structural unit of Chemical Formula 1A in Chemical
Formula 1 may be at least one of, for example, Chemical Formulae
3-1, 3-4 and 3-7. The --Z-- structural unit in Chemical Formula 1
may be one of, for example, Chemical Formulae 4-1, 4-3, 4-5, 4-6,
4-8, 4-10, 4-11, and 4-12. The organic semiconductor compound
including the structural unit represented by Chemical Formula 1 may
include, for example, at least one of structural units represented
by the following Chemical Formula 6.
##STR00019## ##STR00020##
[0058] In Chemical Formula 6, Ra--Rg may each be independently
selected from hydrogen, a substituted or unsubstituted C1-C20
linear or branched alkyl group, or a substituted or unsubstituted
C1-C20 linear or branched alkoxy group, p, q and r may denote a
mole ratio of each structural unit, p/(p+q) may be about 0.5 to
about 0.95, for example, about 0.6 to about 0.9 (e.g., about 0.7 to
about 0.8), and r/(p+q+r) may be about 0.2 or less, for example,
about 0.05 to about 0.15.
[0059] The above Chemical Formula 6 may be, as one example,
Chemical Formula 6-1.
##STR00021## ##STR00022##
[0060] In Chemical Formula 6-1, p, q, and r may denote a mole ratio
of each structural unit, and p/(p+q) may be about 0.5 to about
0.95, for example, about 0.6 to about 0.9, (e.g., about 0.7 to
about 0.8). The variable r may have a value to make r/(p+q+r) about
0.2 or less but may be about 0.05 to about 0.15. A number average
molecular weight (Mn) of the organic semiconductor compound may be
about 5,000 to about 200,000, and a weight average molecular weight
(Mw) of about 10,000 to about 500,000. The organic semiconductor
compound may be a p-type organic semiconductor compound.
[0061] The substituted or unsubstituted C2-C30 heteroaryl group may
be a C2-C30 heteroaromatic ring group including at least one
electron withdrawing imine nitrogen atom and in particular, a
functional group represented by the following Chemical Formula 7,
but is not limited thereto.
##STR00023##
[0062] In Chemical Formula 7, Y may be hydrogen, a C1-C20 linear or
branched alkyl group, or a C3-C20 cycloalkyl group, a C6-C30 aryl
group, a C1-C16 linear or branched alkoxy group, or a C3-C16
cycloalkoxyalkyl group. However, there is no particular limit to a
position where a substituent represented by the above Chemical
Formula 7 is substituted for hydrogen of Chemical Formula 1 and may
not be illustrated here.
[0063] Examples of the C2-C30 heteroaromatic ring group including
at least one electron-withdrawing imine nitrogen atom may include a
thiazolyl group, a thiadiazolyl group, an isoxazolyl group, an
oxadiazolyl group, an imidazolyl group, a pyrazolyl group, a
thiadiazolyl group, a trizolyl group, a tetrazolyl group, a
pyridine group, a pyridazine group, a quinolinyl group, an
isoquinolinyl group, a quinoxalinyl group, a naphthyridinyl group,
a benzoimidazolyl group, a pyrimidopyrimidinyl group, a
benzothiadiazolyl group, a benzoselenadiazolyl group, a
benzotriazolyl group, a benzothiazolyl group, a benzooxazolyl
group, a phenanthrolinyl group, a phenazinyl group, a
phenanthridinyl group, and the like.
[0064] The substituted or unsubstituted C2-C30 heteroaryl group may
be a C2-C30 heteroaromatic ring group including at least one sulfur
atom and selected from the following Chemical Formula 8.
##STR00024##
[0065] In Chemical Formula 8, Y may be hydrogen, a C1-C20 linear or
branched alkyl group, or a C3-C20 cycloalkyl group, a C6-C30 aryl
group, a C1-C16 linear or branched alkoxy group, or a C3-C16
cycloalkoxyalkyl group. When two or more Y are present, Y may be
the same or different from each other. There is no particular limit
to a position where a substituent represented by Chemical Formula 8
may be combined with Chemical Formula 1 and may not be illustrated
here.
[0066] The organic semiconductor compound including the structural
unit represented by Chemical Formula 1 may be prepared by
conventional methods. The organic semiconductor compound including
the structural unit represented by Chemical Formula 1 may be
prepared through reactions of monomers as shown in the following
Reaction Scheme 1.
##STR00025##
[0067] In the Reaction Scheme 1, R.sup.1, R.sup.2, X, Y, Z, p and q
may be the same as in Chemical Formula 1, A.sup.1-A.sup.6 may be
independently reactive groups, for example, a halogen (e.g., Br, I,
Cl, and the like), trialkyltin, and borane, but are not limited
thereto. Trialkyltin may be represented by the following Chemical
Formula 9, and borane may be represented by the following Chemical
Formula 10 or 11.
##STR00026##
[0068] In Chemical Formula 9, R.sub.31-R.sub.33 may be the same or
different and may independently be hydrogen or a C1-C7 alkyl group,
provided that at least one of R.sub.31-R.sub.33 is an alkyl
group.
##STR00027##
[0069] In Chemical Formula 11, R.sub.34-R.sub.37 may be the same or
different and may independently be hydrogen or a C1-C7 alkyl group
provided, as one example, that at least one of R.sub.34-R.sub.37 is
an alkyl group.
[0070] A catalyst may be used in the reaction, of Reaction Scheme 1
and may be an organic metal catalyst represented by the following
Chemical Formulae 12-1 to 12-4.
Pd(L.sub.1).sub.x [Chemical Formula 12-1]
Pd(L.sub.2).sub.4-yCl.sub.y [Chemical Formula 12-2]
[0071] In Chemical Formulae 12-1 and 12-2, L.sub.1 and L.sub.2 may
be ligands, for example, triphenylphosphine (PPh.sub.3),
1,4-bis(diphenylphosphine)butane (dppb),
1,1'-bis(diphenylphosphino)ferrocene (dppf), acetate (OAc),
triphenyl arsine (AsPh.sub.3), and triphenylphosphite
(P(OPh).sub.3), where x may be an integer ranging from 2 to 4,
inclusive, and y may be an integer ranging from 1 to 3,
inclusive.
Ni(L.sub.3).sub.x [Chemical Formula 12-3]
Ni(L.sub.4).sub.3-yCl.sub.y [Chemical Formula 12-4]
[0072] In Chemical Formulae 12-3 and 12-4, L.sub.3 and L.sub.4 may
be ligands, for example, a diphenylphosphinophosphinoalkane (e.g.,
1,3-bis(diphenylphosphino)propane (dppp),
1,2-bis(diphenylphosphino)ethane (dppe),
1,4-diphenylphosphinobutane (dppb), and the like, and a cycloalkene
(e.g., bis(1,5-cyclooctadiene) (COD), and the like)), where x may
be an integer of 2 or 3, and y may be an integer of 1 or 2.
Examples of palladium catalysts may include a palladium (0)
catalyst (e.g., a tetrakis(triphenylphosphine)palladium (0)
compound (Pd(PPh.sub.3).sub.4)), and palladium (II) catalysts
(e.g., 1,4-bis(triphenylphosphine)palladium (II) dichloride
(PdCl.sub.2PPh.sub.32), [1,4-bis(diphenylphosphine)butane]palladium
(II) dichloride (Pd(dppb)Cl.sub.2),
[1,1'-bis(diphenylphosphino)ferrocene]palladium (II) dichloride
(Pd(dppf)Cl.sub.2), palladium (II) acetate (Pd(OAc).sub.2), and the
like).
[0073] Examples of nickel catalysts may include a nickel (0)
catalyst (e.g., a bis(1,5-cyclooctadiene) nickel (0) compound
(Ni(COD).sub.2)), and a nickel (II) catalyst (e.g.,
1,3-diphenylphosphinopropane nickel (II) chloride
(Ni(dppp)Cl.sub.2), 1,2-bis(diphenylphosphino)ethane nickel (II)
chloride (Ni(dppe)Cl.sub.2), and the like). The catalyst may be
used by adjusting its amount according to amounts of the monomers.
For example, the tetrakistriphenylphosphine palladium (0) compound
may be used in an amount of about 0.2 mol % to about 15 mol % with
respect to monomers, and in at least one example embodiment, it may
be used at about 2 mol % to about 10 mol % with respect to
monomers.
[0074] A polymerization solvent, for example toluene,
dimethylformamide (DMF), tetrahydrofuran (THF), N-methylpyrrolidone
(NMP), and the like, may be used. The reaction of the Reaction
Scheme 1 may be performed at about 80 to about 120.degree. C. for
about 6 to about 48 hours under a nitrogen atmosphere. The organic
semiconductor compound may be applicable to an active layer of a
transistor. The transistor may include a gate electrode on a
substrate, a source electrode and a drain electrode facing each
other and defining a channel region, an insulation layer that
electrically insulates the source and drain electrodes from the
gate electrode, and an active layer including the organic
semiconductor compound in the channel region.
[0075] The active layer may be prepared by a solution process of a
composition including an organic semiconductor compound, for
example, screen printing, printing, spin coating, dipping,
ink-jetting, and so on. When the active layer is obtained by a
solution process, the process cost may be reduced. The active layer
may be usefully applied to fabricate a large area device.
[0076] FIG. 1 and FIG. 2 are schematic cross-sectional diagrams
illustrating transistors according to example embodiments. A
transistor according to at least one example embodiment may be a
thin film transistor. The thin film transistor may include a thin
film with a thickness of several nm to several .mu.m. Referring to
FIG. 1, a transistor 10 may include a substrate 12, a gate
electrode 14 on the substrate 12, and an insulation layer 16
covering the gate electrode 14. A source electrode 17a and a drain
electrode 17b defining a channel region may be on the insulation
layer 16. An active layer 18 may be in the channel region. The
active layer 18 may include, for example, an organic semiconductor
compound according to example embodiments.
[0077] Referring to FIG. 2, in a transistor 20, a source electrode
27a and a drain electrode 27b defining a channel region may be on a
substrate 22, and an active layer 28 may be on the channel region.
The active layer 28 may include an organic semiconductor compound
according to example embodiments. An insulation layer 26 may cover
the source electrode 27a, the drain electrode 27b, and the active
layer 28. A gate electrode 24 may be on the insulation layer 26.
The substrates 12 and 22 may include an inorganic material, an
organic material, and/or a composite of an inorganic material and
an organic material. The substrate organic material may include,
for example, a plastic (e.g., polyethylenenaphthalate (PEN),
polyethyleneterephthalate (PET), polycarbonate, polyvinylalcohol,
polyacrylate, polyimide, polynorbornene, and polyethersulfone
(PES)) and the inorganic material may include, for example, glass
and/or metal.
[0078] The gate electrodes 14 and 24, source electrodes 17a and
27a, and drain electrodes 17b and 27b may include a generally-used
metal and/or metal oxide, for example, gold (Au), silver (Ag),
aluminum (Al), nickel (Ni), and/or indium tin oxide (ITO), but is
not limited thereto. The insulation layers 16 and 26 may include a
generally-used insulator of high dielectric constant, for example,
a ferroelectric insulator (e.g., Ba.sub.0.33Sr.sub.0.66TiO.sub.3
(BST, barium strontium titanate), Al.sub.2O.sub.3, Ta.sub.2O.sub.5,
La.sub.2O.sub.5, Y.sub.2O.sub.3, TiO.sub.2), an inorganic insulator
(e.g., PbZr.sub.0.33Ti.sub.0.66O.sub.3 (PZT),
Bi.sub.4Ti.sub.3O.sub.12, BaMgF.sub.4,
SrBi.sub.2(TaNb).sub.2O.sub.9, Ba(ZrTi)O.sub.3(BZT), BaTiO.sub.3,
SrTiO.sub.3, Bi.sub.4Ti.sub.3O.sub.12, SiO.sub.2, SiN.sub.x, AlON
and so on), or an organic insulator (e.g., polyimide,
benzocyclobutane (BCB), parylene, polyacrylate, polyvinylalcohol,
polyvinylphenol, and so on), but is not limited thereto.
[0079] The organic semiconductor compound may be applicable to a
memory device, an organic light emitting element (OLED), a
photosensor, a laser device, and so on.
[0080] FIG. 3 is a schematic cross-sectional diagram illustrating
organic solar cells according to still other example embodiments.
Referring to FIG. 3, the organic solar cell 30 may include an anode
32 on a substrate 31. The substrate 31 may include any transparent
material allowing an external light to enter without any particular
limit. The transparent substrate 10 may be glass and/or a plastic.
Examples of plastics may include polyethyleneterephthalate (PET),
polyethylene naphthalate (PEN), polycarbonate (PC), polypropylene
(PP), polyimide (PI), triacetyl cellulose (TAC), a copolymer
thereof, and/or the like.
[0081] The anode 32 may be made of a high work function material
for hole injection, for example, a transparent oxide (e.g., indium
tin oxide (ITO), fluorine tin oxide (FTO), indium oxide, and/or the
like). A hole transport layer (HTL) 33 may be on the anode 32. The
hole transport layer (HTL) 33 may include a conductive polymer, for
example, poly(3,4-ethylenedioxy-thiophene) (PEDOT) doped with
poly(styrenesulfonate) (PSS) (PEDOT:PSS), polyaniline doped with
poly(styrenesulfonic acid) (PAni:PSS), polypyrrole,
poly(p-phenylenevinylene),
poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene]
(MEH-PPV),
poly[2-methoxy-5-(3,7-dimethyloctyloxy)-1,4-phenylene-vinylene)
(MDMO-PPV), poly(3-alkylthiophene), polythiophene, and the like,
pentacene, CuPc, and/or a triphenyldiamine derivative (TPD).
[0082] A photoactive layer 34 may be on the hole transport layer
(HTL) 33. The photoactive layer may include an electron donor
(p-type semiconductor) material and an electron accepter (n-type
semiconductor) material. The electron donor may be one of the
above-described organic semiconductor compounds. The electron
acceptor may include fullerene with large electron affinity (C60,
C70, C74, C76, C78, C82, C84, C720, C860), a fullerene derivative
(e.g., 1-(3-methoxy-carbonyl)propyl-1-phenyl(6,6)C61 (PCBM)), or a
mixture thereof.
[0083] The organic semiconductor compound and the electron acceptor
may be mixed in the photoactive layer 34 and/or form a bilayered
photoactive layer 34 including two separate thin films. The organic
semiconductor compound and a carbon-based material may be mixed in
a weight ratio of about 1:0.5 to about 1:4. When the organic
semiconductor compound and the carbon-based material are mixed
within the range, efficiency of an organic solar cell may be
improved. The photoactive layer 34 may be formed using a common
method of coating an organic semiconductor compound mixture and an
electron acceptor, for example, spraying, spin coating, dipping,
printing, doctor-balding, sputtering, and/or the like. A thickness
of the photoactive layer 14 may be about 5 nm to about 2000 nm.
[0084] A cathode 35 may be on the photoactive layer 34. The cathode
35 may include an alkali metal (e.g., lithium (Li), sodium (Na),
and/or the like), an alkali-earth metal (e.g., beryllium (Be),
magnesium (Mg), and/or the like), aluminum (Al), transition
elements (e.g., silver (Ag), gold (Au), cobalt (Co), iridium (Ir),
nickel (Ni), osmium (Os), palladium (Pd), platinum (Pt), and/or the
like) a rare earth element, a semi-metal (e.g., selenium (Se),
and/or the like), a metal alloy (e.g., a sodium-potassium alloy, a
magnesium-indium alloy, an aluminum-lithium alloy, and/or the
like), LiF/Al, and/or the like. Although not shown in the drawing,
an electron transport layer (ETL) may be further formed between the
photoactive layer 34 and cathode 35.
[0085] A photocurrent may be generated when a light is absorbed in
the photoactive layer 34 and excites an electron-hole pair, the
excited electron-hole pair may be diffused and reach a interface of
an electron-acceptor and an electron-donor and may be separated
into electrons and holes due to an electron affinity difference of
two materials at the interface. The electrons may move through the
electron acceptor to a cathode 35 while the hole may move through
the electron-donor to an anode 32.
[0086] The following examples are not limiting examples according
to some example embodiments.
EXAMPLES
Synthesis Example 1
Monomer Synthesis
Synthesis Example 1-1
[0087] 2,3-di(3-dodecyloxyphenyl)-5,8-dibromopyrido[3,4-b]pyrazine
is synthesized referring to an article published by Bang-Lin Lee
and Takakazu Yamamoto in Macromolecules 1999, 32, 1375-1382, which
is herein incorporated in its entirety by reference.
[0088] .sup.1H NMR (CDCl3, ppm): d 8.76 (s, 1H), 7.59-7.73 (m, Ph),
7.59-7.73 (m, Ph), 3.86 (t, 4H), 1.71 (m, 4H), 1.35 (m, 36H, CH29),
0.88 (t, 6H, CH3).
Synthesis Example 1-2
[0089] 2,6-dichloro-4,8-bis(N-octylamino)pyrimido[5,4-d]pyrimidine
is synthesized referring to an article published by Takakazu
Yamamoto and Bang-Lin Lee in Macromolecules 2002, 35, 2993-2999,
which is herein incorporated in its entirety by reference.
[0090] .sup.1H NMR (CDCl3, ppm): d 6.86 (t, 2H, J=5.37 Hz, NH),
3.57 (q, 4H, J=6.25 Hz, N--CH2), 1.68 (m, 4H, CH2), 1.36 (m, 20H,
CH25), 0.88 (t, 6H, CH3). 13C{1H} NMR (CDCl3, ppm): d 159.38
(4,8-C), 156.52 (2,6-C), 131.66 (4a, 8a-C), 41.20 (C1 of octyl
group), 31.77 C2, 29.18 C3, 29.16 C4, 28.99 C5, 26.84 C6, 22.64 C7,
14.05 C8.
Synthesis Example 1-3
[0091] 2-bromo-3-hexyl-5-trimethylstannylthiophene is synthesized
as follows.
##STR00028##
[0092] 3-hexylthiophene is reacted with N-bromosuccinimide
(hereinafter, NBS) in the same amount in chloroform at room
temperature for about 15 hours, preparing 2-bromo-3-hexylthiophene.
About 50 mmol of the 2-bromo-3-hexylthiophene is added with about
57 mmol of lithium diisopropylamine (hereinafter, LDA, about 2.0 M
in a mixture of THF/hexane) to about 40 mL of an anhydrous THF
solution during agitation at a temperature of about -80.degree. C.
to about -90.degree. C. The resulting mixture is reacted at the
same temperature for about 20 to about 30 minutes, and a THF
solution of Me.sub.3SnCl (about 50 mmol) is added thereto. The
mixture is agitated at about -50.degree. C. for about 1 hour. After
the reaction, the agitated product is extracted with ether and
water. The acquired organic layer is concentrated and distilled,
obtaining 78% of a yield of a colorless oil product.
[0093] .sup.1H NMR (300 MHz, CDCl3) .delta. (ppm) 0.34 (9H,
CH.sub.3), 0.88 (3H, CH.sub.3), 1.31 (broad, 2nH, --CH.sub.2n-),
1.56 (m, 2H, --CH.sub.2--), 2.55 (t, 2H, Thiophene-CH.sub.2--),
6.84 (s, Thiophene-H).
Synthesis Example 1-4
[0094] 2,5-bis(trimethylstannyl)thiophene (m is 1 in the following
reaction scheme 3) and 2,5-bis(trimethylstannyl)bithiophene (m is 2
in the following reaction scheme 3) is synthesized referring to a
synthesis method illustrated in J. Org. Chem., 1984, 49, 5250,
which is herein incorporated in its entirety by reference.
##STR00029##
[0095] Synthesis of 2,5-bis(trimethylstannyl)thiophene (m is 1 in
the following reaction scheme 3): About 50 mL of a tetrahydrofuran
(THF) solution prepared by using about 3.0 g (12.4 mmol) of
dibromothiophene lowered down to about -50.degree. C. under
nitrogen atmosphere is added to about 18.4 mL (30 mmol) of n-butyl
lithium (1.63 mol of n-BuLi in hexane). The mixture is reacted at
the same temperature for about 30 minutes, and trimethylstannyl
chloride (hereinafter, about 5 g (25 mmol) of Me.sub.3SnCl,) is
added thereto. The resulting mixture is reacted at about
-50.degree. C. for about 4-5 hours.
Water and ether are used to separate an organic layer. The organic
layer is dried by removing the solvent therein. Recrystallization
using ether is performed twice, obtaining about 3.1 g of white
crystal (yield: 60%).
[0096] .sup.1H-NMR (300 MHz, CDCl3) d (ppm) 0.38 (CH3, 18H), 7.38
(2H, Thiophene-H).
Synthesis Example 1-5
[0097] Synthesis of 2,5-bis(trimethylstannyl)bithiophene (m is 2 in
the reaction scheme 3): 2,5-bis(trimethylstannyl)bithiophene is
synthesized according to the same method as in Synthesis Example
1-4 except for using dibromo bithiophene instead of
dibromothiophene.
[0098] .sup.1H NMR (300 MHz, CDCl3) .delta. (ppm) 0.38 (CH3, 18H),
7.08 (d, 2H, Thiophene-H), 7.27 (d, 2H, Thiophene-H).
Example 1
Synthesis of an Organic Semiconductor Polymer Represented by the
Following Chemical Formula 6-1 (3)
##STR00030##
[0100] In Chemical Formula 6-1 (3), p/(p+q)=0.8, and n may indicate
a polymerization degree.
##STR00031##
[0101] About 0.15 g (0.2 mmol) of
2,3-di(3-dodeyloxylphenyl)-5,8-dibromopyrido[3,4-b]pyrazine and
about 0.33 g (0.8 mmol) of
2-bromo-3-hexyl-5-trimethylstannylthiophene synthesized according
to Synthesis Example 1-3 are added to anhydrous dimethyl formamide
(DMF) under a nitrogen atmosphere. While the mixture is lightly
heated, about 0.08 g (0.2 mmol) of
2,5-bis(trimethylstannyl)bithiophene is prepared according to
Synthesis Example 1-4. After the reaction mixture is completely
dissolved, a palladium (0) compound, Pd(PPh.sub.3).sub.4, as a
polymerization catalyst is added thereto in an amount of about 0.1
g, that is, 7.0 mol % based on the total monomers. The resulting
mixture is reacted at about 90.degree. C. for about 12 hours.
[0102] The reaction solution is cooled down to room temperature and
then, filtered, obtaining a polymer solid. The polymer solid is
rinsed with a hydrochloric acid aqueous solution/chloroform twice,
an ammonia aqueous solution/chloroform twice, and water/chloroform
twice in order and then, restored by using methanol, acetone,
methylenechloride, and chloroform in a Soxhlet extraction method.
The polymer is dried, obtaining a red polymer (e.g., yield=45%,
number average molecular weight=28,000, high temperature GPC, a
polystyrene standard).
[0103] FIG. 4 is an .sup.1H NMR spectrum of the organic
semiconductor polymer represented by the above Chemical Formula 6-1
(3). .sup.1H NMR (300 MHz, CDCl.sub.3, ppm) .delta.: 0.86-1.83
(alkyl-CH2), 2.60 (Th--CH2, Head-to-Head), 2.80 (Th--CH2,
Head-to-Tail), 3.92 (b, --O--CH2-), 6.76-7.60 (Th--H, Ph-H), 7.78
(b, Th--H), 8.52 (b, Th--H), 9.13 (s, pyrido[3,4-b]pyrazine-H).
Example 2
Synthesis of an Organic Semiconductor Polymer Represented by the
Following Chemical Formula 6-1 (2)
##STR00032##
[0105] In Chemical Formula 6-1 (2), p/(p+q)=0.8, and n may indicate
a polymerization degree. A navy polymer represented by Chemical
Formula 6-1 (2) is synthesized according to the same method as in
Example 1 except without using the tributylstannyl-bithiophene used
in Example 1 (e.g., yield=52%, number average molecular
weight=32,000, high temperature GPC, a polystyrene standard).
[0106] FIG. 5 illustrates .sup.1H NMR spectrum of the organic
semiconductor polymer represented by the above Chemical Formula 6-1
(2).
[0107] .sup.1H NMR (300 MHz, CDCl.sub.3, ppm) .delta.: 0.84-1.73
(alkyl-CH2), 2.60 (Th--CH2, Head-to-Head), 2.80 (Th--CH2,
Head-to-Tail), 3.90 (b, --O--CH2-), 4.24 (b, --O--CH2-), 6.90-7.64
(Th--H, Ph-H), 7.84 (b, Th--H), 8.55 (b, Th--H), 9.13 (s,
pyrido[3,4-b]pyrazine-H).
Example 3
Synthesis of an Organic Semiconductor Polymer Represented by the
Following Chemical Formula 6-1 (1)
##STR00033##
[0109] In Chemical Formula 6-1 (1), p/(p+q)=0.7, and n may indicate
a polymerization degree. A navy polymer represented by Chemical
Formula 6-1 (1) is synthesized according to the same method as in
Example 1 except without using tributylstannyl-bithiophene (e.g.,
yield=42%, number average molecular weight=28,000, high temperature
GPC, a polystyrene standard).
[0110] .sup.1H NMR (300 MHz, CDCl.sub.3, ppm) .delta.: 0.92-1.67
(alkyl-CH2), 2.60 (Th--CH2, Head-to-Head), 2.80 (Th--CH2,
Head-to-Tail), 4.21 (b, --O--CH2-), 6.90-7.98 (Aromatic --H).
Example 4
Synthesis of an Organic Semiconductor Polymer Represented by the
Following Chemical Formula 6-1 (15)
##STR00034##
[0112] In Chemical Formula 6-1 (15), p/(p+q+r)=0.74,
r/(p+q+r)=0.09, and n may indicate a polymerization degree.
##STR00035##
[0113] About 0.04 g (0.1 mmol) of
2,6-dichloro-4,8-bis(N-octylamino)pyrimido[5,4-d]pyrimidine
according to Synthesis Example 2, about 0.41 g (1.0 mmol) of
2-bromo-3-hexyl-5-trimethylstannylthiophehe according to Synthesis
Example 1-3, and about 0.19 g (0.25 mmol) of
2,3-di(3-dodeyloxylphenyl)-5,8-dibromopyrido[3,4-b]pyrazine) are
added to anhydrous DMF in a reactor under nitrogen atmosphere.
While the mixture is lightly heated, about 0.1 g (0.25 mmol) of
2,5-bis(trimethylstannyl)bithiophene according to Synthesis Example
1-5 is added thereto. When the reaction mixture is completely
dissolved, Pd(PPh.sub.3).sub.4, a palladium (0) compound as a
polymerization catalyst is added thereto in an amount of about 0.1
g, (e.g., 7.0 mol % relative to total mole percent of the
monomers). The mixture is reacted at about 90.degree. C. for about
12 hours.
[0114] The reaction solution is cooled down to room temperature and
is filtered, obtaining a polymer solid. The polymer solid is rinsed
with a hydrochloric acid aqueous solution/chloroform twice, an
ammonia aqueous solution/chloroform twice, and water/chloroform
twice in order and is restored in a soxhlet extraction method by
using methanol, acetone, methylenechloride, and chloroform. The
resulting product is dried, obtaining a red polymer (e.g.,
yield=45%, number average molecular weight=23,000, high temperature
GPC, a polystyrene standard). Referring to NMR analysis, the
hexylthiophene may have a ratio between head-to-tail
(HT):head-to-head (HH) of 0.89:0.11 with a significant
regularity.
[0115] .sup.1H NMR (300 MHz, CDCl3) .delta. (ppm): 0.92 --CH3,
1.10-1.72 (alkyl-CH2), 2.60 (Th--CH2, Head-to-Head), 2.81 (Th--CH2,
Head-to-Tail), 3.94 (b, --O--CH2-, --N--CH2-), 6.95-7.43 (Th--H,
Ph-H), 7.80 (b, Th--H), 8.53 (b, Th--H), 9.13 (s,
pyrido[3,4-b]pyrazine-H).
[0116] The organic semiconductor polymers according to Examples 1-4
are respectively dissolved to have a concentration of about 1.0 wt
% in chlorobenzene. The solution is coated in a spin-coating
method. The coated product is baked at about 100.degree. C. for
about one hour under a nitrogen atmosphere to form a film.
[0117] FIG. 6 illustrates UV-Vis absorption spectrum of the organic
semiconductor compound according to Example 1. As shown in FIG. 6,
the organic semiconductor compound has a broad absorption spectrum
ranging from about 400 nm to about 800 nm.
[0118] Fabrication of an Organic Thin Film Transistor Using an
Organic Semiconductor Polymer
[0119] A glass substrate is cleaned, chromium used as a gate
electrode is deposited thereon at a thickness of about 1000 .ANG.
using, for example, a sputtering method, and SiO.sub.2 used as a
gate insulating layer is deposited on the gate electrode at a
thickness of about 1000 .ANG. using, for example, a CVD method. Au
used as a source-drain electrode is deposited at a thickness of
about 1200 .ANG. on the gate insulating layer using, for example, a
sputtering method. The substrate is rinsed with isopropyl alcohol
for about 10 minutes and is dried before depositing organic
semiconductor polymers. The organic semiconductor polymers is
dipped in an octadecyl trichlorosilane solution diluted to have
about 10 mM of a concentration in chloroform for about 30 seconds,
is rinsed with acetone, and dried, and each organic semiconductor
polymer according to Example 1-4 is respectively dissolved to be
about 1.0 wt % of a concentration in chlorobenzene. The solution is
coated in a spin-coating method and is baked at about 150.degree.
C. for about one hour under a nitrogen atmosphere, fabricating an
OTFT device.
[0120] Fabrication of an Organic Solar Cell Using an Organic
Semiconductor Polymer
[0121] The organic semiconductor polymers according to Examples 1-4
is respectively mixed with a PCBM fullerene
derivativeDeletedTexts([6,6]-phenyl-C.sub.61-butyric acid methyl
ester, a fullerene derivative) in a weight ratio of about 1:1 in a
chlorobenzene solvent, preparing a solution with about 10 mg/mL of
a concentration. An ITO surface is cleaned and PEDOT:PSS (e.g., a
conventional ITO) is spin-coated to be about 40 nm thick. The
coated ITO is baked at about 120.degree. C. for about 60 minutes.
The solution is spin-coated to be about 100 nm thick to form a
photoactive layer on the PEDOT:PSS layer. LiF (about 0.6 nm)/AI
(about 150 nm) is thermally deposited to form a cathode on the
photoactive layer under about 1.times.10.sup.-6 mbar of vacuum,
fabricating an organic solar cell.
[0122] Each organic solar cell is measured regarding current
density-voltage (J.sub.sc-V.sub.oc). The organic solar cells are
operated using a conventional solar simulator, while being radiated
by an AM 1.5 G solar light with an intensity of 100 mW/cm.sup.2.
The organic solar cell is measured regarding current
density-voltage using a conventional source measurement unit. The
intensity of the solar light is calibrated using a silicon solar
cell as a reference.
[0123] The organic solar cell including a mixture of the organic
semiconductor polymer represented by Chemical Formula 6-1 according
to Example 2 and PCBM in a weight ratio of 1:1 is measured
regarding current density-voltage (J.sub.sc-V.sub.oc). The result
is provided in FIG. 7. Based on the current density-voltage curved
line of FIG. 7, the power conversion efficiency (PCE) of the
organic solar cell is calculated using the following Equation
1.
PCE = FF .times. V .varies. I sc P in [ Equation 1 ]
##EQU00001##
[0124] Herein, V.sub.oc may indicate open voltage of a solar cell,
I.sub.sc may indicate a short-circuit current, FF may indicate a
fill factor, and P.sub.in may indicate intensity of incident light
in the solar cell. The organic solar cell including a mixture of
the organic semiconductor polymer represented by Chemical Formula
6-1 (2) according to Example 2 and PCBM in a weight ratio of 1:1
shows efficiency of 2.85%.
[0125] While example embodiments have been particularly shown and
described, it will be understood by one of ordinary skill in the
art that variations in form and detail may be made therein without
departing from the spirit and scope of the claims.
* * * * *